Let’s say you’re curious to know whether there’s evidence that a particular compound is carcinogenic to laboratory animals or to humans. Maybe you’re wondering about UV radiation from tanning beds, or wood dust, or the drug tamoxifen. Do you want to rely solely on the opinion of the compound’s producer or an industry trade association, or might you like to know the views of a panel of independent scientists?

Hearing from the latter was the vision for the U.S.’s Report on Carcinogens. It is a program put in place in 1978 by Public Law 95-622 with amendments to the Public Health Service Act, and managed by the National Institute for Environmental Health Science’s (NIEHS) National Toxicology Program (NTP). Since 1980, twelve issues of the Report on Carcinogens have been published. The current report was about six years in the making and was released in June 2011. It lists 54 substances as “known human carcinogens” —from asbestos and cyclosporin A, to silica and tobacco smoke — and about 180 substances classified as “reasonably anticipated to be human carcinogens.”

But when you’re the maker or user of a compound that is being considered for the report, you might go to great lengths to avoid being listed in it. Daniel Rosenberg at NRDC’s Switchboard lays out the chemical industry ‘s 10-year efforts to shield formaldehyde and styrene from the cancer-causing label. The industry shenanigans caused some delays with the report’s release, but when it was published last year both compounds appeared with their respective cancer labels: styrene listed as “reasonably anticipated to be human carcinogen” and formaldehyde classified as a “known human carcinogen.” The evidence on the association between formaldehyde exposure and cancer (i.e., nasopharyngeal, sinonasal and lymphohematopoietic) is substantial (here, here, here, here, here, here, here, here, here, here, here.)

With the scientific evidence against them, the chemical industry is now following a tried and true strategy. They “blame the messenger” noted Adam Finkel, ScD, MPP, CIH, Professor of Environmental and Occupational Health at the University of Medicine and Dentistry of New Jersey. And with powerful friends on Capitol Hill, the chemical industry can do more than blame the messenger, they can threatened to defund her.

Representative Denny Rehberg (R-MT), chair of the House Appropriations Subcommittee on Labor, Health and Human Services, Education and Related Agencies, (who is also running for the U.S. Senate) drafted an appropriations rider (here at p.52) prohibiting NTP from using any funds for the ROC until the National Academy of Sciences completes a peer review of the ROC’s process and listing criteria for formaldehyde and styrene.

The public health community has taken strong exception to Congressman Rehberg’s rider. More than 70 scientists, physicians and other public health advocates sent a letter last week to Members of Congress explaining the importance of the ROC.

“It] is a model for how to summarize the state-of-the-science on chemicals and cancer. As occupational and environmental health scientists, we firmly believe that building scientific consensus in the U.S. about chemical carcinogens is essential for effectively and efficiently protecting the public’s health and worker health. Furthermore, by providing the public with updated scientific consensus evaluations of the potential cancer risks from workplace and environmental contaminants, it informs American businesses wishing to establish scientifically grounded programs to create safer workplaces and safer products.”

“…With budget riders like this one, the American Chemistry Council (ACC) is working to delay and ultimately destroy the ROC and other government programs that provide the public with unbiased, authoritative scientific assessments of the hazards of its member company’s products. Honest, hard-working Americans and their families rely on Congress to protect their right to know about health risks from toxic chemicals in their homes, workplaces, schools, and consumer products.”

Both formaldehyde and styrene are produced by dozens of companies in the U.S., each in amounts totaling tens of billions of pounds annually – major cash cows for the chemical industry.

That’s millions of dollars in profit potentially threatened by a cancer-causing label. The industry can’t win on the science evidence, so they’ll use their power and influence to blame the messenger and get their friends in the House of Representatives to lead the bandwagon. May wiser heads prevail in the U.S. Senate.